I'd say calling it a "car-based problem" goes to the heart of it!  Soooo...... speaking strictly from an Italian-history-n'-politics viewpoint, I'd say what's wrong with preserving the saints'-days with relative processions/whatever ... means extra personal/human living-time as opposed to bossman's/caesar's worktime -and communal fiestas-of-whatsoever-origin - everything from Viterbo's machine-of-St-Rosa to Siena's Palio - are great collective fun to organise, also get kids into the act feeling they're truly "part of the community" and, in their odd archaic little way, also help people to keep on thinking/feeling in a "community=cooperation=working together NOT for pay =collective creativity" way (yeah I'm ducking under the table as I say this as I can see a furious barrage of objection-brickbats coming!!...;-) )

To solve the cars-problem: so how about we treat it AS SUCH, OK? Why the HECK can't we get/suggest that our local admins. add on extra regional trains for "bridges", ditto special buses to the nearby resort zones (beaches, hill-towns...) all with some kind of festive local tour/food-sampling included in the price!!!???  

Drat it!! - so instead of complaining that saints/fiestas are fostering pollutio, why the heck can't/shouldn't we use these occasions to PROMOTE THE USE OF PUBLIC TRANSPORT - as the "in" way to go where we want to go "en masse" - say using trains/buses instead of cooping ourselves up in energy-wasteful, socially-alienating little private mobile compartments helps us socialize, festivize, enriches our life-experience instead of impoverishing and alienating it plus making the air stink and wrecking our balance of payments????

So in other words, why not make our lovely "bridges" a more "progressive" occasion"???

"Ignoring moralities is always undesirable, but doing so systematically is really worrisome." Mohammed Khatami